ECLS was a randomised controlled trial of 12,208 participants at risk of developing lung cancer in Scotland. The intervention arm received the EarlyCDT-Lung test and, if test positive, low-dose CT scanning six-monthly for up to two years. EarlyCDT-Lung test negative and control arm participants received standard clinical care. Outcomes were assessed at two years post-randomisation using validated data on cancer occurrence, cancer staging, mortality and comorbidities.
At two years, 127 lung cancers were detected in the study population (1.0%).
In the intervention arm, 33/56 (58.9%) lung cancers were diagnosed at stage III/IV compared to 52/71 (73.2%) in the control arm. The hazard ratio for stage III/IV presentation was 0.64 (95% confidence interval 0.41, 0.99). There were non-significant differences in lung cancer and all-cause mortality after two years.
ECLS compared EarlyCDT-Lung plus CT screening to standard clinical care (symptomatic presentation), and was not designed to assess the incremental contribution of the EarlyCDT-Lung test. The observation of a stage-shift towards earlier-stage lung cancer diagnosis merits further investigations to evaluate whether the EarlyCDT-Lung test adds anything to the emerging standard of LDCT.